Clinical Features of Children With MOG-IgG Who Fulfill Criteria of Multiple Sclerosis and Overlapping Disorders

OBJECTIVES: The aim of this study was to report the clinical features, disease-modifying treatment (DMT) response, and outcomes of children with MOG-IgG who fulfill the 2017 McDonald criteria for multiple sclerosis (MS). METHODS: This prospective observational study included children (<18 years) with a suspected acquired demyelinating syndrome (ADS) whose serum or CSF was positive for MOG-IgG, who met the indicated MS criteria, and who had ≥1 year of clinical follow-up. MOG-IgG was tested using live cell-based assays. RESULTS: Of 554 children with confirmed ADS (196 with MOG-IgG), 8 (median age 11 years, interquartile range 9-14) harbored MOG-IgG and fulfilled MS criteria: 2 had typical MS and 6 had overlapping MOGAD-MS features at onset, but 5 of the latter group developed an MS-like course during follow-up. Five of 7 patients with assessable samples were Epstein-Barr virus seropositive at disease onset, and all 8 had persistent silent radiologic activity with lesional location and morphology suggestive of MS, leading to initiation of DMT. All initial treatments were well tolerated, but eventually, 7 of 8 children (88%) required high-efficacy DMT. DISCUSSION: In this pediatric cohort, 4% of patients with MOG-IgG met criteria for MS. The clinical-radiologic spectrum ranged from typical MS to overlapping MOGAD-MS, and patients usually required high-efficacy DMT.